REACTIVE ION ETCHING OF GALLIUM-ARSENIDE IN CCL2F2 AND SICL4 PLASMAS - INFLUENCE OF CHAMBER MATERIAL AND ETCHING MASK

This paper describes the influence of the masking techniques and of the reactor chamber material in reactive ion etching of gallium arsenide in CCl2F2 and SiCl4 plasmas. The etching characteristics are explained by redeposition on surfaces or sidewalls of etched patterns and by interaction with the reactor. Analysis of the etched surfaces by Auger electron spectroscopy (AES) and energy dispersive X-ray spectroscopy (EDX) shows the importance of the masking technique used. Very high-definition GaAs patterning has been performed employing a combination of a SiCl4 gas at a pressure of 5 mTorr, a pure aluminum cover plate material and a nickel mask. A pending issue remains with the hard sidewall film resulting from the high ion energy necessary to achieve anisotropic etching.